Non-Dispersive Infra-Red (NDIR) is a common measurement principle for detecting gases in the atmosphere. NDIR sensors utilize the principle that various gas molecules exhibit substantial absorption at specific wavelengths in the infrared radiation spectrum. The term “non-dispersive” as used herein refers to the apparatus used, typically a narrow-band optical or infrared transmission filter, instead of a dispersive element such as a prism or diffraction grating, for isolating for the purpose of measurement the radiation in a particular wavelength band that coincides with a strong absorption band of a gas to be measured.
The present invention is concerned with addressing problems arising from use of NDIR to detect molecules in a liquid medium, rather than in gas.
This and further objects and advantages will be apparent to those skilled in the art in connection with the figures and the detailed description of the invention set forth below.